Expense Tracker

A full-stack personal finance app: log income and expenses, organize them into categories, set monthly budgets, define recurring transactions, and view charts and monthly summaries.

Tech stack

• Frontend: React + TypeScript (Vite), React Router, Recharts
• Backend: Node + Express + TypeScript
• Database: PostgreSQL
• Auth: JWT tokens with bcrypt-hashed passwords

Project structure

expense-tracker/
├── client/                 # React frontend
│   └── src/
│       ├── api.ts          # fetch wrapper (attaches JWT)
│       ├── auth.tsx        # auth context (login/signup/logout)
│       ├── components/     # Layout, ProtectedRoute, forms
│       └── pages/          # Dashboard, Transactions, Budgets, Recurring, Login, Signup
└── server/                 # Express API
    ├── db/                 # schema.sql + migrations
    └── src/
        ├── db.ts           # PostgreSQL connection pool
        ├── middleware/     # requireAuth (JWT verification)
        └── routes/         # auth, categories, transactions, summary, budgets, recurring

Setup

1. Database

Create the database and tables (PostgreSQL must be installed and running):

CREATE DATABASE expense_tracker;
\c expense_tracker
\i server/db/schema.sql

2. Backend

cd server
npm install
# create server/.env with:
#   DATABASE_URL=postgresql://postgres:YOUR_PASSWORD@localhost:5432/expense_tracker
#   PORT=4000
#   JWT_SECRET=some_long_random_string
npm run dev          # http://localhost:4000

3. Frontend

cd client
npm install
npm run dev          # http://localhost:5173

The Vite dev server proxies /api/* to the backend on port 4000.

API overview

Method	Path	Description
POST	/api/auth/signup	Create an account, returns a token
POST	/api/auth/login	Log in, returns a token
GET	/api/me	Current user (protected)
GET/POST/DELETE	/api/categories	Manage categories
GET/POST/PUT/DELETE	/api/transactions	Manage transactions (GET supports type, category_id, from, to filters)
GET	/api/summary/totals · /by-category · /monthly	Aggregated summaries
GET/POST/DELETE	/api/budgets	Monthly budgets per category
GET/POST/DELETE	/api/recurring	Recurring rules; POST /api/recurring/run generates due transactions

All data routes require an Authorization: Bearer <token> header and are scoped to the logged-in user.

Notes

• Money is stored as NUMERIC, not floating point, to avoid rounding errors.
• DATE values are returned as YYYY-MM-DD strings to avoid timezone shifts.
• Secrets live in server/.env, which is gitignored.